Mark Twain reported it in his book about his travels out West in 1861 while still a young man with his brother, Orion, "Roughing It" - published in 1872.
APPENDIX. A. BRIEF SKETCH OF MORMON HISTORY.
and APPENDIX. B. THE MOUNTAIN MEADOWS MASSACRE.
A quick Google search will find the book free online.
Mark Twain was still a journalist by trade at the time.
438 posted on 07/19/2010 11:40:48 PM PDT by higgmeister
( In the Shadow of The Big Chicken!)